Cooling system for a motor vehicle

ABSTRACT

A cooling system for a motor vehicle, in particular for an electrically powered motor vehicle, havinga first cooling circuit, a second cooling circuit, and at least one coolant circuit,wherein the first cooling circuit has:at least one first component to be temperature-controlleda heat exchanger designed as an indirect condenser for transferring heat betweenthe first cooling circuit and the coolant circuit,wherein the second cooling circuit has:at least one second component to be temperature-controlleda heat exchanger designed as a chiller for transferring heat between the second cooling circuit and the coolant circuit,wherein the first and second cooling circuit can be connected by means of a first connecting section and a second connecting section, and, at least on the first connecting section, a second switching point is arrangedwherein the second switching point connects the first connecting section to the first cooling circuit in such a way that a cooling medium flows completely or at least partially through the first connecting section.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. DE102022110715.9, filed on May 2, 2022, the entirety of which is herebyfully incorporated by reference herein.

The invention relates to a cooling system for a motor vehicle and amethod for operating a cooling system, according to the preamble of theindependent claims.

A cooling system is known from DE 103 00 294 A1, having a first coolingcircuit for dissipating heat from a first heat source, e.g., an electricmotor, a transmission heat exchanger, or an electronic cooling plate.Furthermore, the cooling system has a second cooling circuit, whichincludes a second heat source, such as an internal combustion engine. Aheater core is used to heat the passenger compartment. The first andsecond cooling circuits and the heater core can be selectively connectedto one another with valve means.

The cooling system according to the invention for a motor vehicle withthe features of the independent claims has the advantage that twocooling circuits can not only be coupled directly to one another, butalso heat or cold can be distributed and used as needed in the vehicleby connecting both cooling circuits to a coolant circuit via a chillerand an indirect condenser. This enables flexible management of heatingand cooling of drive components and the passenger compartment of anelectrically powered motor vehicle that keeps energy consumption forheating and cooling low in order to use the amount of energy stored inthe vehicle for the drive as much as possible.

Therefore, in the present case, a cooling system for a motor vehicle isproposed, in particular for an electrically driven motor vehicle,according to the features of claim 1 and the dependent claims, as wellas a method for operating a cooling system according to the features ofclaim 14.

The cooling system according to the invention for a motor vehicle has afirst cooling circuit and a second cooling circuit and at least onecoolant circuit. The two cooling circuits are operated with the samecooling medium, which is usually water mixed with glycol. However, it isalso conceivable to use other cooling media, such as low-viscosity oilsor media specially tailored to the application. The coolant circuit isoperated with a suitable coolant that can provide the necessaryproperties for absorbing, transferring, and releasing heat in a coolantcircuit.

The first cooling circuit contains, for example, at least one firstcoolant pump, which can convey the cooling medium in a suitable mannerin the cooling circuit. The first cooling circuit also contains at leastone component to be temperature-controlled, which can be an electricdrive motor in an especially inventive embodiment. It is alsoconceivable that further components to be temperature-controlled arearranged in the first cooling circuit, such as an inverter forgenerating the alternating current for the electric drive motor, butalso other electrical power circuits that can give off heat duringoperation or when charging a motor vehicle or that must first be heatedunder certain ambient conditions so that the components enter an optimaloperating mode.

A heat exchanger designed as a radiator is also arranged in the firstcooling circuit for transferring heat between the first cooling circuitand the ambient air. Cooling medium, which can exchange heat with theambient air, can thus pass through the radiator. For an improved heatexchange between the radiator and the ambient air, a fan can be arrangedon the radiator, which blows or extracts ambient air over the radiator.The dynamic pressure that occurs when the vehicle is moving, which isalso known as the headwind, also supports the heat exchange. A heatexchanger designed as an indirect condenser is also arranged in thefirst cooling circuit. The indirect condenser transfers heat between thefirst cooling circuit and a coolant circuit. An indirect condenserrefers to when cooling medium that circulates in a cooling circuit isused for heat transfer in the condenser. In contrast to this are directcondensers, in which it is not cooling medium circulating in a coolingcircuit but ambient air that is used for the heat exchange.

The at least one first component to be temperature-controlled and theindirect condenser are arranged in two sections extending parallel toone another, wherein the sections are divided at a first branching pointand brought together at a second branching point. A first switchingpoint is arranged either at the first or second branching point in thiscase. The first switching point is designed in such a way that a coolingmedium circulating in the first cooling circuit can be divided betweenthe two sections. Depending on the required application, a coolingmedium can hereby be conducted more so into the at least first componentto be temperature-controlled or into the indirect condenser. Morecooling medium in the component to be temperature-controlled increasesthe cooling capacity there. On the other hand, the coolant circuitconnected to the indirect condenser is influenced by the regulation ofthe coolant flow in the indirect condenser. More cooling capacity forthe indirect condenser increases the performance and efficiency of theevaporator, for example, and can therefore provide more cold for thetemperature control of the passenger compartment. However, othercomponents of the coolant circuit such as the chiller and a heat pumpheater can also be advantageously influenced in this way.

The distribution of the cooling medium can be made possible inparticular by a suitable switchable or controllable valve device. It isalso conceivable that two switching points, each arranged in onesection, can undertake the division of the volume flow. For thispurpose, the corresponding valve devices provided at the switchingpoints must be controllable.

The second cooling circuit contains, for example, at least one secondcoolant pump, which can convey the cooling medium in a suitable mannerin the cooling circuit. Like the first cooling circuit, the secondcooling circuit contains at least one component to betemperature-controlled. In a preferred manner according to theinvention, this is a battery for storing the electrical energy fordriving the motor vehicle. High demands for temperature control areplaced on the battery, since this also has a major impact on theefficiency of the motor vehicle. Thus, the temperature of the batterymust not be too low, but it also must not exceed certain limittemperatures even with high outside temperatures and a great poweroutput. An ideal operating range for the battery is between 35° C. and45° C. However, further components to be temperature-controlled can alsobe arranged in this cooling circuit, such as an electronic unit forcontrolling driver assistance systems and/or other electroniccomponents.

A heat exchanger designed as a chiller, which is arranged in the secondcooling circuit, transfers heat between the second cooling circuit andthe coolant circuit.

The first cooling circuit and the second cooling circuit can beconnected by means of a first connecting section and a second connectingsection. A second switching point is preferably arranged in the firstconnecting section. This second switching point makes it possible toconnect the first connecting section in such a way that a cooling mediumcirculating in the first cooling circuit flows through the firstconnecting section completely or at least partially. It would also beconceivable to arrange the second switching point in the secondconnecting section so that the inflow of cooling medium into the secondcooling circuit is controlled there. The second switching point can openor close the inflow completely or only partially. However, the inflow ofthe second switching point is advantageously either open or closed inorder to connect or separate the two cooling circuits. Closed here meansthat the flow of cooling medium is largely prevented by a suitable valvedevice, wherein a small leakage of up to 5% of the volume flow cannot beexcluded or can be tolerated.

The first connecting section is arranged downstream of the at leastfirst component to be temperature-controlled in the first coolingcircuit, and the second connecting section is arranged downstream of thefirst connecting section. The two connecting sections can be connectedto one another with a third connecting section, wherein the thirdconnecting section has a check valve. The check valve allows flowthrough the third connecting section in only one direction and blocksflow in the other direction. If the two cooling circuits are separated,the cooling medium in the second cooling circuit circulates through thisthird connecting section. When the cooling circuits are connected, thecheck valve routes the cooling medium in the desired direction, so thatit cannot immediately bypass the second cooling circuit again throughthe third connecting section, since the flow path here would have alower flow resistance.

The radiator arranged in the first cooling circuit is preferablyarranged downstream of the second connecting section. In this case, athird section of the first cooling circuit, in which a fourth switchingpoint is arranged, is located downstream of the second connectingsection and upstream of the radiator. This fourth switching point canconnect the third section to the area upstream of the first branchingpoint, at least partially bypassing the radiator, in such a way that acooling medium circulating in the first cooling circuit flows entirelyor at least partially through the first bypass section.

This allows the flow through the radiator to be controlled and theradiator to be switched off depending on the application, e.g., to heatthe cooling circuit to a certain temperature or to partially orcompletely integrate the radiator to enable a high cooling effectthrough the ambient air.

In the second cooling circuit, a third switching point is arrangedupstream of the chiller, which switching point connects a second bypasssection while at least partially bypassing the chiller in such a waythat a cooling medium circulating in the second cooling circuit flowsthrough the second bypass section completely or at least partially. Theflow of cooling medium through the chiller can thus be controlled andthe heat transfer between the second cooling circuit and the coolantcircuit can thus be regulated.

The chiller usually absorbs heat from the cooling circuit by evaporatingthe coolant. The cooling circuit can thus be cooled in a targeted mannerdepending on the ambient and operating conditions, which is particularlyadvantageous for cooling the at least second component to betemperature-controlled, e.g. the battery. It is also conceivable that,in colder ambient conditions, heat is transferred to the coolant circuitby the heat absorption from the second cooling circuit or the first andsecond cooling circuits, which heat can then be used to heat thepassenger compartment by means of a heat pump heater.

The coolant circuit used in the cooling system includes, for example, atleast one compressor that can appropriately compress the coolant. Thecompressor is preferably designed as an electrically driven compressor.

In addition, at least one heat exchanger designed as an evaporator isarranged in the coolant circuit, which heat exchanger can exchange heatbetween the coolant circuit and the air flowing into the passengercompartment. In particular, the air flowing into the passengercompartment can be cooled by evaporating coolant, thus enablingtemperature control of the passenger compartment at high outsidetemperatures. The evaporator can also be operated in what is known as areheat mode, in which the air is cooled when there is high humidity inthe ambient air and is then warmed up again by a heating device. Thisprevents the vehicle windows from fogging up.

The indirect condenser, which is already arranged in the first coolingcircuit and has already been described, is also part of the coolantcircuit and thus enables the heat exchange between the first coolingcircuit and the coolant circuit.

The chiller, which is already arranged in the second cooling circuit andhas already been described, is also part of the coolant circuit and thusenables the heat exchange between the second cooling circuit and thecoolant circuit.

An internal heat exchanger used for the internal transfer of heat canalso be arranged in the coolant circuit. It is used to transfer heatfrom different areas of the coolant circuit and can thus advantageouslyincrease the efficiency of the coolant circuit.

A heat exchanger designed as a heat pump heater can also be arranged inthe coolant circuit, which heat exchanger enables heat exchange betweenthe coolant circuit and the air flowing into the passenger compartment.This heat pump heater makes it possible, in particular, to heat the airflowing into the passenger compartment by condensing the coolant in theheat exchanger.

The individual components in the first and second cooling circuit areconnected to one another by suitable pipelines and/or hoses. It is alsoconceivable that individual components are combined in a liquidmanagement module. For example, the pumps, valve devices, connectingsections, sensors, but also heat exchangers such as the chiller can bearranged on such a liquid management module. Individual fluid lines andguides can also be advantageously integrated in such a liquid managementmodule.

The components used for control and switching, in order to implement thevarious switching points, can also be represented as switchableindividual valves, as complex valve devices that can map multipleswitching positions in a valve body, or in another suitable manner.

The components to be temperature-controlled in the two cooling circuitscan also be arranged in series or parallel to one another. Additionalswitching points can also be present in order, for example, todisconnect individual components to be temperature-controlled from thecooling circuit or even to control the inflow of cooling medium to anindividual component to be temperature-controlled.

The heat exchangers arranged in the cooling circuits and coolant circuitcan be structurally constructed in a wide variety of ways. For example,the heat exchangers can be constructed from individual pipes, whereinribs can be arranged between the pipes in order, for example, totransfer heat to the air flowing through the ribs or to absorb heat fromthe air. Heat exchangers in a stacked design, in which individual platesare stacked alternately on top of one another and flow channels are thuscreated for at least two fluids, can also be used, in particular for theindirect condenser and the chiller. These are all known constructionsand must be selected and designed appropriately for the requiredapplication.

For the corresponding control and regulation of the switching points,sensors such as pressure or temperature sensors and control units arerequired, which receive the necessary sensor signals and transmitcorresponding control signals to the individual components, inparticular switching points, in particular the switchable orcontrollable valves.

The possible designs of the cooling circuits and the components thereofand the switching positions cannot be presented here conclusively.

Such a cooling system designed according to the invention can beoperated in different advantageous operating methods and can thus covermany everyday situations in a motor vehicle.

The various operating methods are largely dependent on the ambientconditions, in particular the ambient temperature T_(U) and/or thecondition of the vehicle, for example the temperatures T₁, T₂ of thecomponents to be temperature-controlled. The temperature T₁ of the firstcomponent P1 to be temperature-controlled is the temperature of thecoolant at the entry into the first component P1 to betemperature-controlled or, if present, at the entry into a further thirdcomponent P3 to be temperature-controlled, which is present upstream.

The temperature T₂ of the second component P2 to betemperature-controlled is the maximum material temperature occurring inthe second component P2 to be temperature-controlled. In the preferredembodiment according to the invention, it is the maximum celltemperature of the battery.

A first operating method includes starting the motor vehicle at verycold ambient temperatures T_(U) of less than −5° C. to less than −20° C.It is assumed here that the second component to betemperature-controlled is a battery for driving the vehicle and that itis also still very cold and has assumed a temperature T₂ close to orequal to the ambient temperature T_(U), in particular less than −5° C.The aim of this operating method is to get the battery and othercomponents of the vehicle to a higher temperature level as quickly aspossible. Heating the passenger compartment with heat from the coolingsystem is not a priority. At the first switching point, the volume flowis controlled in such a way that no cooling medium or a maximum of 5% ofthe cooling medium circulating in the first cooling circuit flows viathe indirect condenser. The cooling medium thus primarily flows throughthe first component to be temperature-controlled. In this case, it isassumed that this is an electric drive motor with corresponding powerelectronics. Heat is absorbed by the drive motor in this process. Inthis operating method, the second switching point is set in such a waythat the first connecting section is completely or almost completelyopen. The second cooling circuit is thus coupled to the second coolingcircuit. This allows the heat absorbed by the drive motor to be used toheat the battery in the second cooling circuit. The third switchingpoint in the second cooling circuit is switched in such a way that theflow through the chiller is very low or not present at all, inparticular with less than 5% volume flow, and the relevant part of thecirculating volume flow is routed via the second bypass section. Thefourth switching point is switched in such a way that the radiator isbypassed and thus no cooling medium or only a very small proportion ofless than 5% of the cooling medium volume flow is cooled by the ambientair and routed past the radiator via the first bypass section. The heatof the cooling medium is thus distributed in the two cooling circuitsand, in particular, discharged to the battery.

A second operating method in turn covers very cold ambient temperaturesT_(U) of less than −5° C., in particular down to −20° C. The temperatureT₂ in the second component to be temperature-controlled, preferably thebattery, has already assumed a temperature of greater than −5° C. butstill less than 10° C. The motor vehicle has therefore already been inoperation for a certain time and the battery has absorbed or generatedsome heat. It is also conceivable that the battery was already warmed upfrom a previous trip or a charging process. However, the battery isstill too cold for optimal operation, which requires a temperature T₂between 35° C. and 45° C. The first component to betemperature-controlled, preferably the electric drive motor with powerelectronics, continues to heat the two cooling circuits. The two coolingcircuits are therefore still connected to each other; the radiator isswitched off by bypassing it. There is likewise no flow through thecondenser. The chiller can absorb up to 30% of the volume flow, inparticular between 5% and 30%, and thus discharge part of the heat tothe coolant circuit. In the coolant circuit, the heat introduced via theheat pump heater can thus be used to warm up the air flowing into thepassenger compartment. In this case, the first switching point willclose the flow to the condenser, so that a maximum of 5% of the volumeflow will still pass through. The second switching point will becompletely or almost completely open, and the third switching pointcontrols the flow to the chiller in such a way that up to 30%, inparticular at least 5% and at most 30%, of the volume flow is routedthrough the chiller. The fourth switching point closes the flow to theradiator so that a maximum of 5% of the volume flow can still passthrough.

In a further operating method, the operation of the motor vehicle atambient temperatures below 10° C. is covered. The temperature T₂ in thesecond component to be temperature-controlled, preferably the battery,is in an ideal range of from 35° C. to 45° C. The two cooling circuitsare then no longer connected to each other; the radiator is switched offby bypassing it. There is likewise no flow through the condenser.However, the chiller can absorb between 50% and 100% of the volume flowand thus transfer part of the heat to the coolant circuit. The batteryis thus cooled via the chiller, and heat is discharged to the coolantcircuit, which heat can be used to heat up the passenger compartment.The drive motor and the power electronics heat up the first coolingcircuit. The permissible temperatures for these components to betemperature-controlled are between 50° C. and 70° C. so that there is noincreased cooling requirement for the components until the lower limittemperature of 50° C. is reached. The radiator accordingly remainsdisconnected.

In a further operating method, the operation of the motor vehicle atambient temperatures below 10° C. is covered. The temperature T₂ in thesecond component to be temperature-controlled, preferably the battery,is in an ideal range of from 35° C. to 45° C. The temperature T₁ in thefirst component to be temperature-controlled, preferably the electricdrive motor and/or power electronics, is above 50° C. The battery is inan optimal operating mode and is cooled via the chiller by dischargingheat to the coolant circuit. The discharged heat can in turn be used toheat the passenger compartment. The first and second cooling circuitsare separate from each other. The electric drive motor and the powerelectronics must then be cooled to prevent overheating. The radiator isthen integrated into the first cooling circuit in order to enablecooling by the ambient air. If the waste heat from the coolant circuitexceeds the heating requirements of the passenger compartment, part ofthe volume flow is also routed via the condenser. In this case, thecondenser discharges excess heat from the coolant circuit, which is usedto cool the battery using the chiller. Thus, the first switching pointcontrols the flow in such a way that up to 25%, in particular more than5% and less than 25%, of the volume flow reaches the condenser, and thesecond switching point closes completely or almost completely; and thethird switching point controls the flow to the chiller in such a waythat between 50% and 100% of the volume flow is routed through thechiller; and the fourth switching point controls the flow to theradiator in such a way that up to 30%, in particular more than 5% andless than 30%, of the volume flow flows through the radiator.

In a further operating method, the operation of the motor vehicle atambient temperatures between −5° C. and 10° C. is covered. Thetemperature T₂ in the second component to be temperature-controlled,preferably the battery, is in a range of from −5° C. to 10° C. The firstand second cooling circuits are connected to each other. The chillertransfers part of the heat to the coolant circuit and thus provides heatfor heating the passenger compartment via a heat pump heater. There isno flow through the radiator, which means that the heat discharged inthe second component to be temperature-controlled is used to furtherheat the battery and to generate heat for the passenger compartment.Thus, there is no flow through the condenser arranged in the firstcooling circuit either. Thus, the first switching point closes the flowto the condenser so that a maximum of 5% of the volume flow can stillpass through, and the second switching point opens completely or opensalmost completely. The third switching point controls the flow to thechiller so that up to 30%, in particular more than 5% and less than 30%,of the volume flow is routed through the chiller. The fourth switchingpoint closes the flow to the radiator so that a maximum of 5% of thevolume flow can still pass through.

In a further operating method, the operation of the motor vehicle atambient temperatures between 10° C. and 25° C. is covered. Thetemperature T₂ in the second component to be temperature-controlled,preferably the battery, is in a range of from 10° C. to 25° C. Thebattery is not yet operating in an optimal thermal range. Therefore, theheat discharged from the first component to be temperature-controlled,in particular from the electric drive motor and power electronics, isused to heat up the battery. However, the battery itself discharges heatto the coolant circuit via the chiller, which heat is used to heat upthe passenger compartment. An evaporator advantageously arranged in thecoolant circuit is also in operation. The evaporator can thus cool airflowing into the passenger compartment. After cooling, the air is thenwarmed up again in a heat pump heater or other heating device. This isalso called reheat mode and is used to dry the incoming air when theambient air is very humid. Humidity is separated from the air by coolingthe air in the evaporator. In this way, fogging of the windows can beavoided, especially at ambient temperatures below 20° C. and highhumidity. Due to the operation of the evaporator, there is also acooling requirement at the condenser, which means that it is integratedinto the first cooling circuit. However, the radiator is still largelynot in operation, which means that the heat introduced via the condensercan in turn be used to heat up the battery. The first switching pointthus controls the flow in such a way that up to 50%, in particular morethan 5% and less than 50%, of the volume flow reaches the condenser. Thesecond switching point opens completely or almost completely. The thirdswitching point controls the flow to the chiller in such a way that upto 50%, in particular more than 5% and less than 50%, of the volume flowis routed through the chiller. The fourth switching point closes theflow to the radiator so that a maximum of 5% of the volume flow can passthrough.

In a further operating method, the operation of the motor vehicle atambient temperatures between 25° C. and 35° C. is covered. Thetemperature T₂ in the second component to be temperature-controlled,preferably the battery, is in a range of from 25° C. to 35° C. Thebattery has not yet reached its optimum operating temperature but thepassenger compartment needs to be cooled. The two cooling circuits areconnected to each other. Thus, the first component to betemperature-controlled still heats the battery. However, the chiller nolonger discharges heat into the coolant circuit, since there is nolonger any need for heat to heat the passenger compartment, and acooling effect from the chiller on the cooling circuit is not desired.The condenser is integrated into the cooling circuit since theevaporator is active in the coolant circuit to cool the interior, andthus heat builds up in the condenser. The first switching point thuscontrols the flow in such a way that up to 50%, in particular more than5% and less than 50%, of the volume flow reaches the condenser. Thesecond switching point opens completely or almost completely. The thirdswitching point closes the flow to the chiller such that a maximum of 5%of the volume flow can still pass through. The fourth switching pointlikewise closes the flow to the radiator such that a maximum of 5% ofthe volume flow can still pass through.

In a further operating method, the operation of the motor vehicle atambient temperatures between 10° C. and 45° C. is covered. Thetemperature T₂ in the second component to be temperature-controlled,preferably the battery, is in a range of from 35° C. to 45° C. Thebattery has reached the optimum temperature range for operation. The twocooling circuits are connected to each other and the chiller is active.An additional cooling requirement arises at the condenser either due toa reheat operation of the evaporator or due to a pure cooling operationof the evaporator in the coolant circuit. For this purpose, the radiatoris then partly integrated in order to discharge excess heat from thecooling circuits to the environment. The first switching point thuscontrols the flow in such a way that up to 50%, in particular more than5% and less than 50%, of the volume flow reaches the condenser. Thesecond switching point closes completely or almost completely. The thirdswitching point controls the flow to the chiller in such a way that upto 50%, in particular more than 5% and less than 50%, of the volume flowis routed through the chiller. The forth switching point controls theflow to the radiator in such a way that up to 50%, in particular morethan 5% and less than 50%, of the volume flow is routed through theradiator.

Further advantageous embodiments of the invention are described by thefollowing descriptions of the figures. In the figures:

FIG. 1 shows a cooling system according to the invention for a motorvehicle at a glance

FIG. 2 shows a further cooling system according to the invention for amotor vehicle at a glance

FIG. 3 shows a further cooling system according to the invention for amotor vehicle at a glance, wherein the two cooling circuits are coupledand the radiator is bypassed

FIG. 4 shows a further cooling system according to the invention for amotor vehicle at a glance, wherein the two cooling circuits are coupledand the radiator and the chiller are bypassed

FIG. 5 shows a further cooling system according to the invention for amotor vehicle at a glance, wherein some switching points are combined ina module

FIG. 6 is a schematic representation of the control logic of the coolingsystem

PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 shows a cooling system 1 according to the invention for a motorvehicle 2 in schematic form. It consists of a first cooling circuit K1,a second cooling circuit K2, and a coolant circuit K3. The coolingsystem 1 is located in a motor vehicle 2 and controls the temperature ofall important components P1, P2, P3, P4 to be temperature-controlled,such as the drive motor, power electronics, battery, or also electroniccontrol devices or computing units for implementing autonomous drivingfunctions. There is a first component P1 to be temperature-controlled inthe first cooling circuit K1, wherein at least one further component P3could also be arranged therein. The first cooling circuit K1 alsoincludes a first coolant pump 3 and a radiator 11. In the effectiverange of the radiator 11, there is also a fan 12 which, if necessary,can extract or blow ambient air L1 through the radiator 11 and thus hasa cooling effect. The coolant pump 3 is used to convey the coolantthrough the first cooling circuit K1. An indirect condenser 5 is alsoarranged in the first cooling circuit K1.

The first component P1 to be temperature-controlled and the indirectcondenser 5 are arranged in two sections A1, A2 extending parallel toone another, wherein the sections A1, A2 are divided at a firstbranching point 17 and brought together at a second branching point 20.In FIG. 1 , the first switching point V1 is arranged at the secondbranching point 20, which enables the cooling medium circulating in thefirst cooling circuit K1 to be divided between the two sections A1, A2.However, it is also conceivable to arrange this first switching point V1at the first branching point. In this way, cooling medium can be routedas required into the first and third components P1, P3 to betemperature-controlled and/or into the indirect condenser 5. In thiscase, the distribution ratio is dependent on the operating conditionscurrently prevailing in the motor vehicle 2. The cooling medium is usedin the indirect condenser 5 to dissipate heat from the coolant circuitK3. This becomes necessary when the coolant circuit K3 is used forcooling the passenger compartment or for cooling the at least secondcomponent P2, which is advantageously a battery for storing the energyfor driving the motor vehicle 2.

Thus, at cold ambient temperatures T_(U)or when the vehicle 2 isstarted, there is usually no flow through the indirect condenser 5, butrather the cooling medium is only routed through the first component P1to be temperature-controlled. This leads to heating of the coolingmedium. In the cooling system 1 and operating point shown in FIG. 1 , apartial flow of the cooling medium flows through both the indirectcondenser 5 and the first section A1.

The second cooling circuit K2 contains at least one second coolant pump4, which can convey the cooling medium in a suitable manner in thesecond cooling circuit K2. Like the first cooling circuit K1, the secondcooling circuit K2 also contains at least one first component P2 to betemperature-controlled. In a preferred manner according to theinvention, this is a battery for storing electrical energy for drivingmotor vehicle 2. Another component P4 to be temperature-controlled isarranged In FIG. 1 such as an electronic unit for controlling driverassistance systems and/or other electronic components. A heat exchangerdesigned as a chiller 6 is also arranged in the second cooling circuit.

The first cooling circuit K1 and the second cooling circuit K2 can beconnected by means of a first connecting section 9 and a secondconnecting section 10. A second switching point V2 is arranged in thefirst connecting section 9. However, the second switching point V2 couldalso be arranged in the second connecting section 10. The secondswitching point V2 makes it possible to connect the first connectingsection 9 in such a way that a cooling medium circulating in the firstcooling circuit K1 flows through the first connecting section 9completely or at least partially. In this case, the first connectingsection 9 is arranged downstream of the at least first component P1 tobe temperature-controlled in the first cooling circuit K1, and thesecond connecting section 9 is arranged downstream of the firstconnecting section 10. The two connecting sections 9, 10 are connectedto one another with a third connecting section 14, wherein the thirdconnecting section 14 has a check valve 15. The check valve 15 allowsflow through the third connecting section 14 in only one direction andblocks flow in the other direction. Thus, when the second switchingpoint V2 is closed, the cooling medium in the second cooling circuit K2circulates in the third connecting section 14 via the check valve 13. Ifthe second switching point V2 is open, the cooling medium circulatescoming from the first cooling circuit K1 through the first connectingsection 9 and, due to the check valve 13, cannot flow through the thirdconnecting section 14 and thus circulates once in the second coolingcircuit K2 and exits it, through the second connecting section 10, backinto the first cooling circuit K1.

The radiator 11 arranged in the first cooling circuit K1 is arrangeddownstream of the second connecting section 10. A third section A3 ofthe first cooling circuit K1, in which a fourth switching point V4 isarranged, is located downstream of the second connecting section 10 andupstream of the radiator 11. A first bypass section 15, which can beswitched by the fourth switching point V4, connects the third section A3to the area upstream of the first branching point 17.

This fourth switching point V4 connects the third section A3 to the areaupstream of the first branching point 17 so that a cooling mediumcirculating in the first cooling circuit K1 flows through the firstbypass section 15 completely or at least partially. In this way, theradiator 11 can be completely or partially bypassed and the coolingcapacity of the first cooling circuit K1 can thus be regulated by theambient air L1. If a lot of heat has to be dissipated from the firstcooling circuit K2, the flow can be routed through the radiator 11 in atargeted manner in order to dissipate excess heat from the coolingsystem 1. By interconnecting the first and second cooling circuits K1,K2, heat can also be dissipated from the second cooling circuit K2directly via the ambient air L1 if required. In FIG. 1 , the fourthswitching point V4 is switched in such a way that a partial flow isrouted over the radiator 11 and through the first bypass section 15.

In the second cooling circuit K2, a third switching point V3 is arrangedupstream of the chiller 6, which switching point connects a secondbypass section 16 while at least partially bypassing the chiller 6 insuch a way that a cooling medium circulating in the second coolingcircuit K2 flows through the second bypass section 16 completely or atleast partially. The flow of cooling medium through the chiller 6 canthus be controlled and the heat transfer between the second coolingcircuit K1 and the coolant circuit K3 can thus be regulated. In FIG. 1 ,the third switching point V3 is controlled in such a way that a partialflow is routed both through the chiller 6 and through the bypass section16. The chiller 6 absorbs heat from the second cooling circuit K2 byevaporating the coolant. The second cooling circuit K2 can thus becooled in a targeted manner as a function of the ambient and operatingconditions, which is advantageous for cooling the battery.

The coolant circuit K3 arranged in the cooling system 1 contains acompressor 7. This compressor 7 is preferably electrically driven. Inaddition, at least one heat exchanger designed as an evaporator 8 isarranged in the coolant circuit K3, which evaporator can exchange heatbetween the coolant circuit K3 and the air L2 flowing into the passengercompartment. Thus, the air L2 flowing into the passenger compartment canbe cooled by evaporating coolant, thus enabling temperature control ofthe passenger compartment at high outside temperatures T_(U). However, areheat function to dry incoming moist air L2 is also possible. In thiscase, the air L2 is first cooled so that atmospheric moisture is removedand then heated up again with a subsequent heater, e.g. a heat pumpheater 18. This heat pump heater 18 allows heat to be exchanged betweenthe coolant circuit K3 and the air L2 flowing into the passengercompartment. Thus, air L2 flowing into the passenger compartment isheated by condensing the coolant in the heat pump heater 18.

The previously described indirect condenser 5 is likewise part of thecoolant circuit K3 and enables the heat exchange between the firstcooling circuit K1 and the coolant circuit K3. The chiller 6, which isarranged in the second cooling circuit K2 and has already beendescribed, is also part of the coolant circuit K3 and thus enables theheat exchange between the second cooling circuit K2 and the coolantcircuit K3. An internal heat exchanger 19 is used to transfer heat andcan transfer heat from different areas of the coolant circuit K3. Theefficiency of the coolant circuit K3 can thus be increased.

The individual components of the cooling circuits K1, K2 and the coolantcircuit K3 are fluidly connected to one another by suitable hose or pipeconnections.

The cooling system 1 also contains temperature sensors 21, 22, 23 fordetecting the ambient temperature T_(U) and temperatures T₁ and T₂ atthe components P1, P2 to be temperature-controlled. Temperature sensor21 for measuring the ambient temperature T_(U) is attached to the motorvehicle 2 at a suitable point, so that the ambient temperature T_(U) canbe detected without direct solar radiation or other directly acting heatsources.

Temperature sensor 22 is located in the coolant flow at the inlet to thefirst component P1 to be temperature-controlled. If other components tobe temperature-controlled, such as the third component P3 to betemperature-controlled, are arranged upstream of the first component P1to be temperature-controlled, then temperature sensor 22 is located inthe coolant flow at the inlet of the components to betemperature-controlled that are located furthest upstream. Temperaturesensor 23 is located in the second component P2 to betemperature-controlled, in thermally conductive contact with thematerial of the component P2. The position of temperature sensor 23 isto be selected in such a way that the measured temperature T₂corresponds to the maximum material temperature occurring in the secondcomponent P2 to be temperature-controlled. In the preferred embodimentaccording to the invention, it is the maximum cell temperature of thebattery. The temperature sensors forward the measured signals to asuitable control unit 24, which carries out the necessary switching ofthe switching points V1, V2, V3, V4 in the cooling system 1, e.g.directly or via another vehicle control unit 26 of the motor vehicle 2.

FIG. 2 shows the cooling system 1 according to the invention at aspecific operating point. In contrast to the operating point shown inFIG. 1 , the cooling medium here flows completely or predominantlythrough the chiller 6 in the second cooling circuit K2. The thirdswitching point V3 is set in such a way that most of the cooling mediumgoes through the chiller 6. The two cooling circuits K1 and K2 areseparate. The second switching point V2 is switched in such a way thatthere is no flow through the first connecting section 9. The first andsecond cooling circuits K1, K2 are therefore not connected to oneanother. In the second cooling circuit K2, the cooling medium circulatesover the third connecting section 14 and the check valve 13 as well asthrough the components P2, P4 to be temperature-controlled and thechiller 6.

FIG. 3 shows the cooling system 1 according to the invention at afurther operating point, wherein the first and second cooling circuitsK1, K2 are connected to one another here. The cooling medium can thusflow from the first cooling circuit K1 into the second cooling circuitK2 and from there into the components P2, P4 to betemperature-controlled and then through the chiller 6 in a first partialflow and through the second bypass section 16 and then again from thesecond cooling circuit K2 into the first cooling circuit K1 in a secondpartial flow. The fourth switching point has closed the flow to theradiator 11 so that there is no flow through it and the cooling mediumis routed via the first bypass section 15. A closed flow means that onlya volume flow of less than 5% is permitted, which flows through theradiator 11 as permitted leakage. The indirect condenser 5 and the firstcomponent P1 to be temperature-controlled are each controlled by thefirst switching point V1 with partial flows flowing through.

FIG. 4 shows the cooling system 1 according to the invention at afurther operating point. The first and second cooling circuits K1, K2are also connected to one another here. There is no flow through theradiator 11, but rather the cooling medium is routed through the firstbypass section 15. The fourth switching point V4 is switchedaccordingly. There is then no more flow through the chiller 6. Heat canthen no longer be exchanged between the second cooling circuit K2 andthe coolant circuit K3. The first component P1 to betemperature-controlled and the third component P3 to betemperature-controlled are then arranged parallel to one another. Afifth switching point V5, which is arranged at a branch to the parallelstrands, enables the two components P1, P3 to be temperature-controlledto be selectively integrated into the first cooling circuit K1. It wouldthus be possible to divide the volume flow of the cooling medium againinto the two components P1, P3 to be temperature-controlled, accordingto a specific distribution ratio. In this way, an increased coolingrequirement of an individual component P1, P3 to betemperature-controlled can be taken into account or, for example, one ofthe components P1, P3 can be completely excluded from cooling if thereis no cooling requirement. This reduces the flow resistance in thecooling circuit K1 and can therefore also increase efficiency.

FIG. 5 shows a further cooling system according to the invention,wherein several switching points V1, V2, V4 as well as the check valve12 and the connecting sections 9, 10, 14 are combined in a liquidmanagement module 25 in this case.

This means that the control functions of the individual switching pointsV1, V2, V4 are implemented in a single control valve or in severalindividual components arranged next to one another in a liquidmanagement module 25, in particular 3/2-way valves or other controllablevalves. The connecting sections 9, 10, 14 are also integrated into theliquid management module 25 and could be constructively injected, forexample in the load-bearing elements of the liquid management module 25,or fixed directly to the liquid management module 25 as fixed hoses orpipe connections. The check valve 13 can also be structurally integratedinto the liquid management module, for example by means of an insertedcomponent. The idea of a liquid management module 25 as an integratingcomponent can be taken even further and supplemented, for example, byincorporating the coolant pumps 3, 4 or the chiller 6 or by furtherswitching points and sensor elements. The interconnection and operatingpoints described here are not influenced by the structural design butonly represent further possible exemplary embodiments of the invention.

FIG. 6 shows a schematic representation of the control logic of thecooling system 1 with which the method for operating the cooling system1 of the motor vehicle 2 is carried out. The temperatures are shown asnecessary input variables T_(U), T₁, T₂. The control unit 24 processesthis input data and sends corresponding control commands to the controlpoints V1, V2, V3, V4. A vehicle control unit 26 could serve as anadditional data source or control aid, e.g. to incorporate otherparameters of the motor vehicle 2 into the control of the cooling system1. For example, a control logic could also advantageously influence thecooling system 1 in anticipation of a hill climb, which is recognized bynavigation data, or also incorporate other operating parameters of themotor vehicle. The exact structure of the electronic control logic 24,26 is not shown hereby. It is also conceivable to use several controldevices that communicate with one another or to process all the datacentrally and then to distribute the corresponding control commands viaa bus system. The constructive and electrical design of this control cantherefore not be presented here conclusively.

The specification can be understood with respect to the followingnumbered paragraphs:

Numbered Paragraph 1: A cooling system (1) for a motor vehicle (2), inparticular for an electrically powered motor vehicle, having

-   -   a first cooling circuit (K1), a second cooling circuit (K2) and        at least one coolant circuit (K3),    -   wherein the first cooling circuit (K1) has:        -   at least one first component (P1) to be            temperature-controlled        -   a heat exchanger designed as an indirect condenser (5) for            transferring heat between the first cooling circuit (K1) and            the coolant circuit (K3),    -   wherein the second cooling circuit (K2) has:        -   at least one second component (P2) to be            temperature-controlled        -   a heat exchanger designed as a chiller (6) for transferring            heat between the second cooling circuit (K2) and the coolant            circuit (K3),        -   wherein the first and second cooling circuit (K1, K2) can be            connected by means of a first connecting section (9) and a            second connecting section (10), and, at least on the first            connecting section (9), a second switching point (V2) is            arranged        -   wherein the second switching point (V2) connects the first            connecting section (9) to the first cooling circuit (K1) in            such a way that a cooling medium flows at least partially            through the first connecting section (9).

Numbered Paragraph 2: The cooling system (1) according to NumberedParagraph 1, characterized in that the first component (P1) to betemperature-controlled and the indirect condenser (5) are arranged intwo mutually parallel sections (A1, A2), wherein the sections (A1, A2)are divided at a first branching point (17) and brought together at asecond branching point (20), wherein a first switching point (V1) isarranged at the first or second branching point (17, 20) and the firstswitching point (V1) is switchable in such a way that cooling medium canbe divided into the sections (A1, A2).

Numbered Paragraph 3: The cooling system (1) according to any one of thepreceding Numbered Paragraphs, characterized in that the firstconnecting section (9) is arranged downstream of the at least firstcomponent (P1) to be temperature-controlled in the first cooling circuit(K1), and the second connecting section (10) is arranged downstream ofthe first connecting section (9).

Numbered Paragraph 4: The cooling system (1) according to any one of thepreceding Numbered Paragraphs, characterized in that the firstconnecting section (9) and the second connecting section (10) areconnected to a third connecting section (14) and the third connectingsection (14) has a check valve (13).

Numbered Paragraph 5: The cooling system (1) according to any one of thepreceding Numbered Paragraphs, characterized in that a heat exchangerdesigned as a cooler (11) for transferring heat between the firstcooling circuit (K1) and the ambient air (L1) is arranged downstream ofthe second connecting section (10).

Numbered Paragraph 6: The cooling system (1) according to NumberedParagraph 5, characterized in that a fourth switching point (V4) isarranged in a section (A3) which is arranged downstream of the secondconnecting section (10) and upstream of the cooler (11), which switchingpoint connects a section (A3) to the area upstream of the firstbranching point (17) by means of a bypass section (15), at leastpartially bypassing the cooler (11) in such a way that the coolingmedium circulating in the first cooling circuit (K1) completely or atleast partially flows through the first bypass section (15).

Numbered Paragraph 7: The cooling system (1) according to any one of thepreceding Numbered Paragraphs, characterized in that, in the secondcooling circuit (K2), a third switching point (V3) is arranged upstreamof the chiller (6), which switching point connects a second bypasssection (16), at least partially bypassing the chiller (6) in such a waythat a cooling medium circulating in the second cooling circuit (K2)completely or at least partially flows through the second bypass section(16).

Numbered Paragraph 8: The cooling system (1) according to any one of thepreceding Numbered Paragraphs, characterized in that the at least onefirst component (P1) to be temperature-controlled in the first coolingcircuit (K1) is an electric drive motor and in that the at least onesecond component (P2) to be temperature-controlled in the second coolingcircuit (K2) is a battery for storing electrical energy for driving themotor vehicle.

Numbered Paragraph 9: The cooling system (1) according to any one of thepreceding Numbered Paragraphs, characterized in that the first and/orsecond cooling circuit (K1, K2) has at least a second or third component(P3, P4) to be temperature-controlled and these are arranged in seriesor parallel to one another.

Numbered Paragraph 10: The cooling system (1) according to any one ofthe preceding Numbered Paragraphs, characterized in that the coolantcircuit (K3) has a heat pump heater (18) for heat exchange between thecoolant circuit (K3) and air (L2) flowing into the passengercompartment.

Numbered Paragraph 11: The cooling system (1) according to any one ofthe preceding Numbered Paragraphs, characterized in that at least two ofthe switching points (V1, V2, V3, V4) are implemented in a commonswitching valve.

Numbered Paragraph 12: The cooling system (1) according to any one ofthe preceding Numbered Paragraphs, characterized in that at least one ofthe switching points (V1, V2, V3, V4) is designed as an adjustablevalve.

Numbered Paragraph 13: The cooling system (1) according to any one ofthe preceding Numbered Paragraphs, characterized in that at least two ofthe switching points (V1, V2, V3, V4) are arranged in a liquidmanagement module (25) together with at least one connecting section (9,10, 14).

Numbered Paragraph 14: A method for operating a cooling system (1) for amotor vehicle (2), in particular for an electrically powered motorvehicle, having

-   -   a first cooling circuit (K1), a second cooling circuit (K2), and        at least one coolant circuit (K3),    -   wherein the first cooling circuit (K1) has:        -   at least one first component (P1) to be            temperature-controlled        -   a heat exchanger designed as an indirect condenser (5) for            transferring heat between the first cooling circuit (K1) and            the coolant circuit (K3),    -   wherein the second cooling circuit (K2) has:        -   at least one second component (P2) to be            temperature-controlled        -   a heat exchanger designed as a chiller (6) for transferring            heat between the second cooling circuit (K2) and the coolant            circuit (K3),        -   wherein the first and second cooling circuit (K1, K2) can be            connected by means of a first connecting section (9) and a            second connecting section (10), and, at least on the first            connecting section (9), a second switching point (V2) is            arranged        -   wherein the second switching point (V2) connects the first            connecting section (9) to the first cooling circuit (K1) in            such a way that a cooling medium circulating in the first            cooling circuit (K1) flows completely or at least partially            through the first connecting section (9).

LIST OF REFERENCE SIGNS

-   -   1 Cooling system    -   2 Motor vehicle    -   3 First coolant pump    -   4 Second coolant pump    -   5 Indirect condenser    -   6 Chiller    -   7 Compressor    -   8 Evaporator    -   9 First connecting section    -   10 Second connecting section    -   11 Radiator    -   12 Fan    -   13 Check valve    -   14 Third connecting section    -   15 First bypass section    -   16 Second bypass section    -   17 First branching point    -   18 Heat pump heater    -   19 Internal heat exchanger    -   20 Second branching point    -   21 Ambient temperature sensor    -   22 First internal temperature sensor    -   23 Second internal temperature sensor    -   24 Control unit    -   25 Liquid management module    -   26 Vehicle control unit    -   A1 Section    -   A2 Section    -   A3 Section    -   K1 First cooling circuit    -   K2 Second cooling circuit    -   K3 Coolant circuit    -   P1 First component to be temperature-controlled    -   P2 Second component to be temperature-controlled    -   P3 Third component to be temperature-controlled    -   P4 Fourth component to be temperature-controlled    -   L1 Ambient air [    -   L2 Air flowing into the passenger compartment    -   V1 First switching point    -   V2 Second switching point    -   V3 Third switching point    -   V4 Fourth switching point    -   V5 Fifth switching point    -   T_(U) Ambient temperature    -   T₁ Temperature in the first component to be        temperature-controlled    -   T₂ Temperature in the second component to be        temperature-controlled

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1. A cooling system for a motor vehicle, in particular for anelectrically powered motor vehicle, having a first cooling circuit, asecond cooling circuit and at least one coolant circuit, wherein thefirst cooling circuit has: at least one first component to betemperature-controlled a heat exchanger designed as an indirectcondenser for transferring heat between the first cooling circuit andthe coolant circuit, wherein the second cooling circuit has: at leastone second component to be temperature-controlled a heat exchangerdesigned as a chiller for transferring heat between the second coolingcircuit and the coolant circuit, wherein the first and second coolingcircuit can be connected by means of a first connecting section and asecond connecting section, and, at least on the first connectingsection, a second switching point is arranged wherein the secondswitching point connects the first connecting section to the firstcooling circuit in such a way that a cooling medium flows at leastpartially through the first connecting section.
 2. The cooling systemaccording to claim 1, wherein that the first component to betemperature-controlled and the indirect condenser are arranged in twomutually parallel sections, wherein the sections are divided at a firstbranching point and brought together at a second branching point,wherein a first switching point is arranged at the first or secondbranching point and the first switching point is switchable in such away that cooling medium can be divided into the sections.
 3. The coolingsystem according to claim 1, wherein the first connecting section isarranged downstream of the at least first component to betemperature-controlled in the first cooling circuit, and the secondconnecting section is arranged downstream of the first connectingsection.
 4. The cooling system according to claim 1, wherein the firstconnecting section and the second connecting section are connected to athird connecting section and the third connecting section has a checkvalve.
 5. The cooling system according to claim 1, wherein a heatexchanger designed as a cooler for transferring heat between the firstcooling circuit and the ambient air (L1) is arranged downstream of thesecond connecting section.
 6. The cooling system according to claim 5,wherein a fourth switching point is arranged in a section which isarranged downstream of the second connecting section and upstream of thecooler, which switching point connects a section to the area upstream ofthe first branching point by means of a bypass section, at leastpartially bypassing the cooler in such a way that the cooling mediumcirculating in the first cooling circuit completely or at leastpartially flows through the first bypass section.
 7. The cooling systemaccording to claim 1, wherein in the second cooling circuit, a thirdswitching point is arranged upstream of the chiller, which switchingpoint connects a second bypass section, at least partially bypassing thechiller in such a way that a cooling medium circulating in the secondcooling circuit completely or at least partially flows through thesecond bypass section.
 8. The cooling system according to claim 1,wherein the at least one first component to be temperature-controlled inthe first cooling circuit is an electric drive motor and in that the atleast one second component to be temperature-controlled in the secondcooling circuit is a battery for storing electrical energy for drivingthe motor vehicle.
 9. The cooling system according to claim 1, whereinthe first and/or second cooling circuit has at least a second or thirdcomponent to be temperature-controlled and these are arranged in seriesor parallel to one another.
 10. The cooling system according to claim 1,wherein coolant circuit has a heat pump heater for heat exchange betweenthe coolant circuit and air flowing into the passenger compartment. 11.The cooling system according to claim 1, wherein least two of theswitching points are implemented in a common switching valve.
 12. Thecooling system according to claim 1, wherein least one of the switchingpoints is designed as an adjustable valve.
 13. The cooling systemaccording to claim 1, wherein at least two of the switching points arearranged in a liquid management module together with at least oneconnecting section.
 14. A method for operating a cooling system for amotor vehicle, in particular for an electrically powered motor vehicle,having a first cooling circuit, a second cooling circuit, and at leastone coolant circuit, wherein the first cooling circuit has: at least onefirst component to be temperature-controlled a heat exchanger designedas an indirect condenser for transferring heat between the first coolingcircuit and the coolant circuit, wherein the second cooling circuit has:at least one second component to be temperature-controlled a heatexchanger designed as a chiller for transferring heat between the secondcooling circuit and the coolant circuit, wherein the first and secondcooling circuit can be connected by means of a first connecting sectionand a second connecting section, and, at least on the first connectingsection, a second switching point is arranged wherein the secondswitching point connects the first connecting section to the firstcooling circuit in such a way that a cooling medium circulating in thefirst cooling circuit flows completely or at least partially through thefirst connecting section.